Songhai: 3x gold from encampments/pillaging, and land units have War Canoes (2x embarked defense and additional embarked sight) and Amphibious promotions
Ottomans: 1/3 naval maintenance and all melee naval units have Prize Ships (Defeated enemy naval unit joins your side) promotion
Siam: 50% increase to food, culture, and faith from friendly city-states
England: +2 naval movement and one extra Spy
Those are the only changes I notice to the civs' unique abilities, though I think there are some unique buildings that got some tweaks related to faith as well.